Technical Field
Embodiments of the present invention relate generally to wireless digital communication systems and, more specifically, to a system and method for communication between radio frequency identifier (RFID) interrogators.
Description of the Related Art
A radio frequency identifier (RFID) network typically includes a plurality of RFID interrogators, each configured to read data from certain RFID tags that are positioned in sufficiently close proximity. This data is then conventionally transmitted upstream via a backhaul network to a server configured to process the data or log the data for later processing. Each RFID tag is configured to store certain data, which may comprise read-only, writeable, or measured data. For example, an RFID tag may store a product code or serial number for an associated article of manufacture. An RFID interrogator retrieves data stored within the RFID tag via a radio frequency (RF) communication transaction.
Certain RFID tags are referred to as “passive,” and typically derive operating power by harvesting ambient RF energy. When the RFID interrogator attempts to read a passive RFID tag, sufficient ambient RF energy is provided to the passive RFID tag to power up and operate. To transmit stored data to the RFID interrogator, passive RFID tags typically employ backscatter techniques, which modulate reflected RF energy originating from the RFID interrogator. Certain other RFID tags are referred to as “active,” and typically derive operating power from a battery or other robust power source. To transmit stored data to the RFID interrogator, active RFID tags typically generate a modulated RF signal. In both cases, the RFID interrogator conventionally transmits data to the RFID tag, and the RFID tag transmits stored data back to the RFID interrogator. In both cases, RFID interrogators are typically configured to avoid interference with each other, for example by remaining inactive while nearby RFID interrogators transmit RF energy to perform read transactions with associated RFID tags.
One challenge in deploying an RFID network is implementing the backhaul network, which must be connected to each RFID interrogator. One approach to implementing the backhaul network involves coupling a wired data network, such as a wired Ethernet network, to each RFID interrogator. Implementing a conventional wired backhaul network for the RFID interrogators is generally expensive and complex, with each different RFID interrogator requiring that a separate cable be routed and coupled to the RFID interrogator from a wired data switch. Alternatively, the backhaul network may be conventionally implemented using a standard wireless data networking technology, such as the industry standard “WiFi” or related technologies. Implementing a backhaul network using conventional wireless data networking technologies generally eliminates much of the cost and complexity associated with a wired data network, but introduces different problems, such as potential interference from other legitimate users of the wireless data networking technology.
As the foregoing illustrates, what is needed in the art is a more efficient technique for interconnecting RFID interrogators.